Adherence and long-acting injectable antipsychotics in schizophrenia: an update
Nonadherence to antipsychotics poses a major problem in the long-term management of schizophrenia. Subjective measures of adherence (self-reports, provider reports) are unreliable, more objective methods (e.g., electronic monitoring, plasma levels) are neither available in clinical practice, nor are they infallible. Risk factors include history of nonadherence, substance use, limited insight, treatment with antidepressants, medication-induced cognitive impairment, hostility, and violent behavior. Nonadherence results in partial or no response to antipsychotic treatment with many adverse consequences, including higher mortality. A recent meta-analysis somewhat surprisingly failed to prove higher adherence to long-acting injectable antipsychotics (LAI) than to oral antipsychotics. However, unexpectedly high adherence in the reviewed trials suggests selection bias. This is further supported indirectly by the findings from two large observational studies from Finland. They showed that LAI, as compared to oral formulations of the same drugs, were associated with a significantly lower risk of rehospitalization and drug discontinuation. Prescription data from the Czech Republic indicate that LAI are underutilized. Contrary to traditional assumptions, patients with previous exposure to LAI appraised them favorably and frequently preferred them in the long-term treatment. LAI may be considered not only for nonadherent, relapsing or difficult-to-manage patients, but also for actively participating, well-informed patients with insight.
Key words: Adherence, long-acting injections, antipsychotics, schizophrenia